1. Field of the Invention
The present invention relates to a manufacturing method for an antenna module to be incorporated in wireless terminal equipment such as a portable telephone.
2. Description of the Related Art
In recent years, wireless terminal equipment such as a portable telephone has widely been put to practical use with an increase in communication demand. An antenna module is usually incorporated in a housing of the wireless terminal equipment, so as to ensure a receiving function in carrying the equipment. The antenna module is required to essentially have required electrical characteristics concerning a resonance frequency, a band width, a gain, etc. and additionally have a feature that the module is fit for a reduction in size and weight of the equipment. Further, a manufacturing method for such an antenna module suitable for mass production is required, so as to reduce the cost of the antenna module.
As such a conventional antenna module to be incorporated in a portable telephone, there are known a platelike inverted F-shaped antenna 2 as shown in FIG. 1 and an S-shaped antenna 4 as shown in FIG. 2. These antenna modules are formed by a sheeting technique, so that they are not necessarily fit for a reduction in size of the equipment. Further, to ensure required electrical characteristics, a high accuracy is required not only for an external size of each element but also for a gap size between an antenna element and a ground element, thus necessitating a high working technique.
FIG. 3 shows another conventional antenna module fit for a reduction in size and weight, which is now in practical use. This antenna module is integrally constructed of a resin molding and a metal conductor foil by the use of a mold. As shown in FIG. 3, the antenna module is provided with a ground element 6 and an antenna element 8 each formed from a metal conductor foil, a loop element 10 electrically connected to the antenna element 8, and an element support 12 formed from an insulator, for supporting the ground element 6, the antenna module 8 and the loop element 10.
The element support 12 is formed with a hollow portion 12A extending in the longitudinal direction for the purposes of reducing a weight and obtaining a required permittivity of the element support 12. However, considering the shape of the mold to be used in manufacturing the antenna module shown in FIG. 3, only one antenna module can be obtained by a single molding step. Accordingly, the mass production of plural antenna modules is difficult.